Drainage and septic tanks
Nothing on the visit sampled a grease trap, opened the flat over a former cafe or tested a drain the trap lid was not lifted. What has to stay undecided?
The inside of the grease trap, the old cafe use, and the drain beneath the unlifted lid all have to stay undecided. Nothing on the visit sampled the trap, opened up the flat's history over a former cafe, or tested the drain, because the lid was not lifted. A grease trap is there to hold fat before it enters the drainage. The survey has not seen the contents, has not decided the trap still serves this flat, and has not decided who must maintain it. The lid stayed down. That is the limit.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
Grease traps are common where a cafe kitchen used to discharge, and a flat above that space can inherit the same buried fitting. You only know this trap by lifting the lid, which did not happen. The surveyor may see a cover in a floor or a yard and a plan that mentions the old cafe. They cannot see the basket, the fat level or the outlet. Sampling did not take place. The former use explains why the trap is in the sentence. It does not describe its condition.
Ask the solicitor who is responsible for the grease trap under the lease, the former cafe or the flat, because the survey cannot assign that duty. Ask a drainage firm to lift the lid and look, if access is allowed. The visit did not do it and did not test the drain. Do not treat a closed cover as a blockage, and do not treat it as a clean trap. The undecided points are the contents, the responsibility and the pipe the lid is hiding.
What should you ask your surveyor?
- Where is the grease trap cover, and who can give access to it?
- Did any plan or lease page actually name the former cafe, or was that only background?
- Was any fat, smell or slow waste noted without the lid being lifted?
What are the typical next steps?
- Leave the trap contents, the cafe history and the drain untested.
- Ask the solicitor who must maintain the trap.
- Have a drainage firm lift the lid only with proper access.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
Does a flat over a former cafe still need a grease trap?
The survey has not decided that. A trap may still be on the drainage even though the cafe has gone, and it may be redundant. The lid was not lifted, so the contents and the connection were not seen. Whether this flat's waste still passes through it is unknown. The solicitor and a drainage firm have to resolve use and responsibility. The report does not.
Can you assume the drain is blocked because the lid stayed down?
No. A closed lid is the reason the drain was not tested, not evidence that it is blocked. The survey did not sample the trap and did not run water through it. Blockage and a clear pipe are both still possible. Ask for the lid to be lifted with access agreed. Until then the drain stays undecided.